#include <iostream>
using namespace std;

void swap(int &a, int &b){
    int t=a;
    a=b;
    b=t;
}

int main(){
    int x=3,y=4;
    cout<<"x="<<x<<",y="<<y<<endl;
    swap(x,y);
    cout<<"x="<<x<<",y="<<y<<endl;
    int &f=y;
    cout<<"f="<<f<<endl;
    return 0;
}
